1. Field of the Invention
A method consistent with the present invention relates to a resynchronization method in wireless ad-hoc network environments, and more particularly, to a resynchronization method for performing a resynchronization process in a case that an arbiter for synchronizing a wireless ad-hoc network environment stops its operations.
2. Description of the Related Art
A wireless ad-hoc network environment is synchronized by a wireless access device operating as an arbiter. For example, in the Institute of Electrical and Electronic Engineers (IEEE) 802.11 standard, all wireless access devices connected to the wireless ad-hoc network environment can be arbiters synchronizing the wireless ad-hoc network environment every beacon frame by using a backoff scheme. Further, in the 802.15.3 standard, only one arbiter exists while the wireless ad-hoc network environment is maintained, and beacon frames issued in the same periods by an arbiter are broadcast to and synchronize each wireless access device.
Accordingly, the 802.11 standard is not suitable for isochronous services since the beacon frame synchronizing the wireless ad-hoc network environment is not issued in the same periods. However, even though a wireless access device operating as an arbiter stops its operations due to, for example, sudden malfunctions, the ad-hoc network environment can be synchronized by another wireless access device since all wireless access devices connected to the wireless ad-hoc environment can be an arbiter.
Whereas the 802.15.3 standard has advantages for isochronous services since the environment is synchronized by beacon frames broadcasting in the same intervals from one arbiter. However, the synchronization is carried out by one arbiter, so that, if the arbiter stops its operations due to, for example, occurrences of situations such as power outages or the like, a new arbiter should be selected since the wireless ad-hoc network environment is not synchronized, and a resynchronization process should be performed by the newly selected arbiter.
As in the 802.15.3 standard, a resynchronization process by a newly selected arbiter in the wireless ad-hoc network environment for which one arbiter exists is generally as follows. That is, if a current arbiter stops its operations so that a situation occurs wherein beacon frames are not broadcast for a certain period of time, the wireless access devices temporarily stop their transmission and reception operations. The wireless access devices wait for an arbitrarily set period of time and each issues a beacon frame, and, at this time, a wireless access device that first issues a beacon frame becomes a new arbiter. Thereafter, in a process configuring the wireless ad-hoc network environment, the current arbiter is handed over to another arbiter according to the attributes of a wireless access device to be connected.
However, in the above scheme, each wireless access device itself issues a beacon frame after waiting for an arbitrarily set period of time from the time when its transmission and reception operations are halted with beacon frame broadcasts stopped, causing a problem that a resynchronization can be delayed by contentions between wireless access devices if the wireless access devices each have the same period of time arbitrarily set. Further, it cannot be guaranteed that the most suitable arbiter is selected in a resynchronization process, so that an arbiter may be handed over later, which causes a problem of incurring an overhead in wireless ad-hoc network environments.